1. Field of the Invention
The present invention relates to a method of processing silver halide color photographic photosensitive material. In particular, the present invention provides a bleach-fixing solution having particularly excellent desilverizability and stability.
2. Description of the Prior Art
Recently in the processing of silver halide color photographic photosensitive materials, an excellent development finish, reduction of delivery time and reduction of environmental pollution have been eagerly demanded. Therefore, facilitation, acceleration and stabilization of the process and the reduction of environmental pollution are now importantproblems.
For the facilitation of the desilverization step, a bleach-fixing process wherein the bleaching and fixing are conducted at the same time is the most easy. In this process, ordinarily an iron/organic acid complex is used as an oxidant, a thiosulfate is used as a fixing agent and a sulfite is used as a preservative. However, it is well known that since the bleach-fixing solution comprises both oxidant and reducing agent, its oxidizing power is weaker than that of an ordinary bleaching solution and its stability is disadvantageously lower than that of the latter.
The bleach-fixing solution has, therefore, a low desilverization velocity and various techniques of accelerating the desilverization have been proposed. For example, the bleach-accelerating agents used in the techniques thus proposed heretofore include compounds having a mercapto group or disulfide group described in U.S. Pat. No. 3,893,858, West German Patent No. 1,290,812, Japanese Patent Unexamined Published Application (hereinafter referred to as "J.P. KOKAI") Nos. 53-32736 and 53-28426 and Research Disclousre No. 17129 (July, 1978); thiazolidine derivatives described in J.P. KOKAI No. 50-140129; thiourea derivatives described in J.P. KOKAI No. 53-32735 and U.S. Pat. No. 3,706,561; iodides described in J.P. KOKAI No. 58-16235; polyethylene oxides described in West German Patent No. 966,410; polyamine compounds described in Japanese Patent Publication for Opposition Purpose (hereinafter referred to as "J.P. KOKOKU") No. 45-8836; compounds described in J.P. KOKAI Nos. 49-42434 and 58-63940; and iodine and bromine, ions. However, no technique capable of sufficiently accelerating the desilverization has been developed yet. Although a technique of improving the oxidizing power of the bath by lowering pH of the bath is described in J.P. KOKAI No. 58-18632, the cyan dye is converted into a leuco dye and satisfactory results cannot be obtained, while an excellent bleaching power is obtained.
The stability of the bleach-fixing solution can be improved by, for example, a method wherein the amount of a sulfite ion used as the preservative is increased, a method wherein a reducing agent such as ascorbic acid is used or a method wherein pH of the bath is elevated to 7 or higher, particularly 8 or higher. However, in these methods, the silver bleaching power is reduced. Thus, both acceleration and stabilization could not be attained simultaneously.
Under these circumstances, no stable bleach-fixing bath having an excellent bleaching power has been developed yet.
On the other hand, techniques of remarkably saving water have been developed for the purpose of saving resources, reducing envinmental pollution and facilitating the process (i.e., to make pipes unnecessary) as described in J.P. KOKAI Nos. 56-70549, 57-132146, 57-8543, 58-18631, 59-184343, 59-184345 and 58-14834.
However, in the technique comprising the processing with the bleach-fixing solution followed by the above-mentioned water-saving processing, when the desilverization and subsequent steps are conducted rapidly in 3 min, the washing-out of the components of the color developer and those of the bleach-fixing solution becomes insufficient and, as a result, the stability of the image cannot be maintained for a long time. This problem is more serious when a highly active 2-equivalent coupler is used for the purpose of saving silver. Particularly a stain formation with tie after the processing is a serious problem.
Techniques for preventing the formation of the stain by incorporating a special component in the photosensitive material are described in J.P. KOKAI Nos. 49-11330, 50-57223, 56-85747 and 58-115438 and J.P. KOKOKU No. 56-8346. However, the effects of them are yet insufficient.
A technique for preventing the stain formation by processing with a buffering agent in a stabilizing, bath to control pH of the finished film to about 3 to 6.5 is well known and has been described in J.P. KOKAI No. 57-8543. In addition, a technique of lowering pH of the film with a stabilizing solution containing ammonium ion after the processing is described in J.P. KOKAI No. 60-135942. Such a technique of lowering pH of the film of the photosensitive material is yet unsatisfactory, since it reduces the stability of a yellow image, though it has some effect of preventing the stain formation.